Manifold sheets coated with lactone and related chromogenous compounds and reactive phenolics and method of marking



April 1966 G. J. SULLIVAN 3,244,548

MANIFOLD SHEETS COATED WITH LACTONE AND RELATED CHROMOGENOUS COMPOUNDS AND REACTIVE PHENOLICS AND METHOD OF MARKING Filed Aug. 31, 1961 BASE WEB, ORIGINAL TRANSFER COATING ON BACK CONTAINING BlS(p-AM|NOPHENYL)PHTHALAN OR PHTHALIDE TRIPH ENYLM ETHANE DERIVATIVE IIII'I'M ADHERENT COATING ON FACE CONTAINING PHENOL AS COLOR DEVELOPER BASE WEB, DUPLICATE TRANSFER COATING 0N BACKIOPTIONALLI INVENTOR. GEORGE .1. SULLIVAN Ib/z m 01 711mm,

ATTORNEY United States Patent MANIFOLD SHEETS bohrun WITH LACTONE AND RELATED CHRGMOGENOUS COMPUUNDS AND REAQTIV E PHENOLIC AND METHOD OF MARKING George James Sullivan, Scarborough Township, Ontario, Canada, assignor to Burroughs Corporation, Detroit, Mich., a corporation of Michigan Filed Aug. 31, 1961, SB!- No. 135,193 16 Claims. (Cl. 117-362) This invention relates to arrangements and methods for producing dark colored marks from colorless materials, which ordinarily appear white, or from materials which are only lightly colored. These materials usually are incorporated in coatings on webs, the coatings conveniently being on paper rolls, ribbons, or sheets. As used in the present specification and in the appended claims, both achromatic colors, that is, grays and black, and chromatic colors are included; dark colored materials may be dark gray or black; or they may be chromatic colors likewise of low brillance, such as dark blues, greens, purples, reds, and browns whether of low or high saturation, or even vivid colors of high saturation and high brilliance, such as bright blues, greens, and reds. All of these colors are distinguished markedly from colorless materials, or from lightly colored materials having white or light gray colors or having pastel shades of high brilliance but low saturation.

Marking systems of these general types have been proposed which utilize as chromogenous compounds the leuco, or simple amino-substituted triphenylmethane, substances such as leuco-malachite green, crystal violet, and ethyl violet, or the corresponding para-amino-substituted triphenylmethyl carbinols. From the standpoint of color stability and ease of developing the colored forms, it has been found advantageous in some marking or image duplicating systems to utilize the lactone forms, which are p-amino-substituted diphenylphthalides, corresponding to the above-mentioned leuco forms, or the lactones or colorless bases of the rhodamine dyes.

It is known that lactone materials of these types dis solved in an oily liquid, may be brought into contact with particles of an inorganic material such as attapulgite, halloysite, magnesium trisilicate, calcium silicate, or basic aluminum silicate to produce dark colored products. Weak acids such as acetic acid and tartaric acid also have been suggested for use with lactone color forming compounds to develop dark colored products, but in practice the clay-like materials or other inorganic solids such as those mentioned above have been used for this purpose. In addition to acetic and tartaric acids, diluted stronger acids also have been suggested generally for this purpose, but without naming any specific acids, strengths, or dilutions, and there is no indication that any specific inorganic acids or any other carboxylic acids have been found to be desirable or particularly suitable. The weaker inorganic acids, such as boric acid, also appear to have little if any eflicacy in producing dark colored products from the chromogenous lactone compounds. Thus it is neither necessary nor especially probable that a material having the chemical constitution and dissociation properties recognized as characteristic of acids will be desirable or particularly suitable for such a purpose. Even when using the inorganic color developing materials mentioned above, the solid colored products tend to lose much or all of their color in the presence of substantial amounts of moisture, tend to deteriorate with age, and are noticeably unstable to irradiation as from sunlight or fluorescent lamps.

It is an object of the present invention, therefore, to provide novel and improved web coatings, methods of marking and duplicating or otherwise developing dark 3,244,548 Patented Apr. 5, 1966 colored materials, and such materials themselves, which avoid one or more of the disadvantages of the prior art.

It is another object of this invention to provide new coating arrangements and associated color-developing systems for use with lactone and related chromogenous compounds, so as to provide novel, spirit-soluble and oilsoluble, dark-colored materials or marks having generally improved characteristics such as color intensity, speed of color development, insensitivity to various polar solvents including water, and resistance to radiation, oxidizing agents, and other environmental influences which tend to cause deterioration of the colored product.

It is a further object of this invention to provide a manifolded set arrangement, utilizing a novel combination of colorless or lightly colored smudge-proof materials, for producing one or more copies by transfer of color-generating substances from the back surface of each sheet in the set to the face of the next lower sheet to form marks or characters of improved high contrast and durability on the lower sheet or sheets immediately upon writing or printing on the top sheet.

It is still another object of this invention to provide new and improved methods of developing dark-colored materials from chromogenous compounds, useful in particular for producing marks on a substrate, and for making.

the web has an adherent coating which comprises such phenolic substance in an amount equal to at least ten percent of the weight of the coating but accessible to other materials coming into contact with portions of the coating; other-Wise specified, the web carries such substance evenly distributed in amounts of from 0.2 to 8 grams per 1,000 square inches of web surface. In a modification the adherent coating comprises a film-forming material containing, as a finely dispersed phase, a phenolic compound having the above-mentioned action on such chromogenous compounds. Alternatively the web carries the specified phenolic substance transferable upon local impact from the web to a surface contiguous therewith, Where contact may be made with the chromogenous compound on such continguous surface.

In accordance with a feature of the invention, a manifolded set comprises a first base web having on one side a transfer coating containing the above-identified chromogenous compound, which is transferable upon impact from the coating to a surface contiguous therewith, and a second base Web carrying on at least one active surface a phenolic substance selected from the group listed above, the first and second webs being maintained disposed to gether in face to face relationship with the transfer coating in contiguity with the active surface, whereby, upon such-impactinlocalized areas, a dark colored material is produced locally by the action of the phenolic substance carried on the active surface in opening the bond from the central methane carbon atom to the heterocyclic oxygen atom to permit quinonoid resonance in the chromogenous compound transferred to the active surface. In'accordance with a more specific feature of the invention, the transfer coating is made up of a filmformingmaterial which is rupturable upon impact and which contains as a finely dispersed phase numerous cells of a solvent liquid vehicle in which the chromogenous compound is dissolved. In a related but broader aspect ofthe invention, either one of the two constituents the chromogenous compound and the phenolic substance-is dissolved in the solvent liquid vehicle present as the numerous-cellsin the transfer coating on the first base web, while the other of theseconstituents is bonded to the, second web in an adherent coating thereon but accessible to the first-selected constituent when it comes into contact with portions of the adherent coating.

In accordance with a method feature of the invention, the method of developing dark colored materials from chromogenous compounds comprises bringing the aforementionedchromogenous compound into reaction contact with the phenolic substance. In the method of marking on a substrate, the chromogenous compound is brought into contact, in areas on the substrate where marking is desired, with the phenolic substance to produce marks in such areas of a dark colored material formed by the action ofthe phenolic substance on the chromogenous compound. The invention also encompasses the new composition of matter comprising the dark colored substance obtained by intimate contact of the phenolic substance with the colorless or lightly colored chromogenous compound.

In a method ofduplicating, in accordance with the invention, two colorless or lightly colored substances are provided, these substances being the aforementioned chromogenous compound and the phenolic substance, and the method then comprises forming, on the surface of a master sheet, deposits of a preselected one of these two substances in areas representing an image to be duplicated but with mirror-reversed image elements. Thereafter a solution of the remaining one-of the two substances in a solvent liquid is appliedto the surface of a duplicate sheet, and this duplicate sheet surface, wetted with the solvent liquid containing that remaining one of the two substances, is pressed against the master sheet surface to effect transfer by the solvent liquid of portions of the image representing deposits of the preselected one of the two substances from the master sheet surface to the duplicate sheet surface in areas thereon representing theimage, whereby a duplicate image is formed on the duplicate sheet surface of dark-colored material produced by the action of the phenolic substance on the chromogenous compound. In a modification of the method of duplicating, in accordance with the invention, the remaining one of the two substances is carried at all times on the surface of the duplicate sheet, and a liquid which is a solvent for the preselected one of the two substances is applied to that surface, which then is pressed, thus wetted, against the master sheet surface to cause portions of the preselected one of the two substances deposited thereon to dissolve in the liquid and to be transferred into contact with the remaining one of the two substances, carried on the duplicate sheet surface, in the areas thereon representing the image, whereby a duplicate image of the dark colored material is formed on the duplicate sheet'surface.

For a better understanding of the present invention, together with other and further objects thereof, reference is had to the following description taken in connection with" the accompanying drawing, and its scope will be pointed out in the appended claims.

The single figure-of the drawing shows in exploded view two manifolding units, suitable for use together in face to face contiguity, as suggested by the bracket at the left of the figure, in a manifolded set with or without additional similar manifolding units. These units are shown as coated webs, illustrated in cross section with the thicknesses of the base webs and of the coatings on the web surfaces greatly exaggerated for convenience of illustration.

The manifolded set illustrated comprises a first, or original, base web 11 having on one side a transfer coating 12 containing a color-generating substance which is transferable upon impact from the coating 12, to a surface contiguous therewith. The coating 12 may be simply the solid substance to be transferred bonded to the web 11 by a solid adhesive, but preferably a liquid vehicle is provided, dispersed throughout a solid film, vwhich carties the substance to be transferred,,as will be discussed in greater detail hereinbelow. Thus the first base-web 11 preferably has the coating 12 made up of a film-forming material which is rupturable upon impact and which;

contains as a finely dispersed phase numerous cells of a solvent liquid vehicle. A second base web 13 also is provided, having on one side an adherent coating 14, and the first and second webs are maintained disposed together in face to face relationship with the respective transfer and adherent coatings, in contiguity with each other.

Each of the coatings 12 and 14 includes a color-generating constituent such that the two constituents, although each is colorless or only lightly colored, together form upon intimate contact with each other a dark colored product. One coating constituent has the form of a colorless or lightly colored chromogenous compound which includes as its major functional arrangement the molecular structure having a triphenylmethane group'with, a bondfrom the methane carbon atom thereof. to the heterocyclic oxygen atom. Another coating constituent is provided in the form ofa phenolic compound, which preferably is selected,

from the group consisting of phenol, each of the dihydric phenols, each of the trihydrie phenols, l-naphthol, and Z-naphthol. One of these two coating constituents is dissolved in the solvent liquid vehicle present as the numerous cells in the transfer coating 12 on the first base web 11, and the other of the coating constituents is bonded to the second web 13 in-the adherent coating 14 thereon but is accessible to other materials cominginto contact with portions of theadherent coating 14, whereby, upon .locallimpact and rupture of the transfer coating 12, releasing the liquid vehicle containing the onecoating constituent. from some of the cells onto the contiguous. adherent coating 14, contact iselfected between the two coating constituents to produce a dark. colored material by the action of the phenolic substance in opening the bond from the methane-carbon atom tothe heterocyclic oxygen atom to permit quinonoidresonance in the chromogenous compound.

Accordingly, a manifolded set may be arranged with the phenolic substancein the transfer coating 12. The web 11 then carries, transferable therefrom upon local impact to a surface contiguous therewith, the selected phenolic substance, so that the Web is adapted, upon such impact and transfer of portions of the substancelocally to the contiguous surface of the, web 13,- for contact thereon of the portions so transferred with the chromogenous compound to develop a dark colored material by the action of the substance so transferred on the chromogenous compound. However, one advantage of the phenolic substances as color developers for these chromogenous compounds is their solubility in many vehicles. Thus the transfer coating 12 may be made up of a hydrophilic film-forming material such as casein, gelatin, a cellulose derivative, or polyvinyl alcohol, applied as an aqueous composition containing an oily liquid vehicle emulsified therein so that the film-forming material is rupturable upon impact and contains as a finely dispersed phase numerous microscopic droplets or cells of the liquid vehicle. The vehicle may be any one of numerous suitable nonvolatile solvent vehicles, such as castor oil, sperm oil, a chlorinated phenyl ether, or benzyl butyl phthalate, and carries dissolved therein the phenolic substance. With this arrangement the adherent coating 14 contains the chromogenous compound bonded to the web 13 by a cementitious material.

It may be noted that a web with a transfer coating, such as the above-mentioned coatings containing a phenolic substance, may take the form of a fabric ribbon impregnated with ribbon-inking oils which carry the substance to be transferred. This type of ribbon may be used in a typewriter for applying the transferable substance to the surface of a sheet carrying the chromogenous compound or other color-reactive material. Dark colored marks or characters then are formed on the sheet by impact of the types through the ribbon, even though the ribbon and the sheet surface are white in color prior to use. On the other hand, some systems for developing dark colored marks are operative with a transfer ribbon or sheet containing the solid transferable material in a simple frangible transfer medium of, for example, solid wax.

While excellent results are obtainable with the manifolded set arrangement just described in which the phenolic substance is transferred, it usually is more economical and generally preferable to include the chromogenous compound in the transfer coating. Accordingly, the web 11 in the manifolded set has a transfer coating 12 on the back containing the specified chromogenous compound, which in most cases may be viewed as a compound related to, or a derivative of, triphenylmethane, more specifically a 1,l-bis(p-aminophenyl) phthalan compound or a 3,3-bis(p-aminophenyl)phthalide compound, usually substituted. The second base web 13 then carries the phenolic color-developing substance on at least one active surface 14, whereby upon marking impact a dark colored material is produced by the action of the phenolic substance, carried on the active surface or coating 14, on the chromogenous compound transferred to the active surface.

The Web 13 in this embodiment of the invention preferably carries the phenolic substance evenly distributed in amounts of from 0.2 to 8 grams per 1,000 square inches of web surface. When the web is of a suitable material, its surface regions may be impregnated by dissolving the phenolic substance in a volatile solvent, applying the solution to the web, and drying. Preferably the web carries an adherent coating on its face containing the phenol substance as the color developer. Ordinarily the phenol will not adhere as a coating to most paper or film web materials without the use of an adhesive or film-forming substance. The coating nevertheless readily may contain over half phenol substance by weight, and in any case the web should have on one side an adherent coating comprising a phenol bonded to the web in an amount equal to at least ten percent of the weight of the coating. For this purpose the adherent coating conveniently comprises a film-forming material containing the phenolic compound as a separate, finely dispersed phase but accessible to other materials coming into contact with portions of the coating, so that the coated web is adapted for de- 6 veloping dark colored material at a portion of the coating when a colorless or lightly colored chromogenous compound of the type described herein comes into contact with that portion of the coating.

The use in large proportions of an impervious adhesive material which would coat or cover most of the phenolic substance in the coating would render the coating practically ineffective by preventing contact of much of the developer substancewith any chromogenous compound brought onto the surface of the coating. Assuming that the coating is sutficiently pervious and the developer material therein is accessible, one means for bringing the chromogenous compound into contact with portions of the coating to develop colored material is to incorporate numerous very small capsules, containing the chromogenous compound dissolved in a solvent liquid, in or on the same coating. With this arrangement local impact or pressure on the coating causes the capsules to break locally, bringing about contact of the two materials within the single coating to develop the dark colored marks. Desirable marking sensitivities and color-free unmarked surfaces are more easily obtained, however, when the coated web is used as a manifolding unit in a manifolded set, as illustrated for example in the drawing. Of course, the developer substance in the coating 14 would be accessible to chromogenous materials coming into contact with the coating if the developer substance adheres with exposed areas to the top portion of the coating, even though the adhesive which joins the developer substance to the face of the web 13 is itself impervious. If the chromogenous compound is carried by a liquid vehicle which permits the chromogenous compound to penetrate to the developer substance in the coating 14, it obviously would not be necessary that the developer substance in the coating be accessible to all materials which might reach the coating.

While a great many phenolic substances are useful as developers for triphenylmethane derivatives of the bis-(paminophenyhphthalan type which are discussed in detail hereinbelow, the developer substances recommended for incorporation in embodiments of the present invention preferably are selected from the group consisting of phenol, each of the dihydric phenols, each of the trihydric phenols, l-naphthol, and 2-naphthol. Phenol itself, having the structural formula has generally excellent color-developing properties in contact with the various chromogenous compounds. Phenol, however, has a. relatively low melting point even in the pure condition, and thus may change to the liquid state under certain ambient conditions, especially in the presence of water. Also, its afiinity for water, its odor, and its effect on the skin ordinarily make it more suitable for use in certain stain-free duplicating methods embodying the present invention than as a coating constituent or component in a manifolded set of sheets.

Among the dihydric phenols, resorcinol and pyrocatechol also have very good color-developing characteristics in most embodiments of the present invention. With respect to hydroquinone, or quinol, having the structural formula its developing characteristics, while substantial, tend to be considerably weaker with many of the chromogenous compounds.

The trihydric phenols, although they also will effect the production of colored forms when in elficient contact with the chromogenous compounds in a suitable color-developing arrangement, ordinarily are not preferred. These include phloroglucinol' The compound 1,2,4-benzenetriol, or hydroxyquinol, having the structural formula r OH is perhaps the least active of these color-developing substances in such arrangements; it often develops a. good, dark color when it is brought into especially effective reaction contact with the chromogenous compound by heat, but may develop little or no appreciable color without the heating.

Naphthol, and more specifically either Z-naphthol (beta-naphthol) or l-naphthol (alpha-naphthol), having the structural formulas respectively, also give very good results as. colorv devel-v opers for the chromogenous compounds in the arrange? ment of the present invention.

Problems may arise due to the solubility of some of these phenols, not only in the oily liquid vehicles or other organic solvents in which they may be dissolved, but also in aqueous media or even in dried coating films. This might cause diificulty with certain phenol materials in transfer coatings which employ, as was mentioned above, a phenol dissolved in an oil which then is emulsified in a hydrophilic aqueous film former, coated, and dried to form a hardened film containing oil droplets. There may be a tendency for the phenol to penetrate the film and reach the exposed surface of the coating without any rupture of the film. This difiiculty may be overcome, however, by encapsulating minute droplets of the vehicle containing the phenolic substance in thin, pressure-rupturable shells of water-impervous material before the vehicle is mixed into the aqueous film former. Applying the mixture to the web then provides a clean transfer coating.

Alternatively the phenol, as discussed above, may be applied to a web, such as the web 13, as an adherent coating 14, in which the phenol is accessible to chromogenous materials coming into contact with the coated face of the web. Many film-forming or cementing materials are available for use as bonding agents. Various agents have different tendencies to coat the phenol and so partially obstruct access thereto of the chromogenous material, but the proportion of phenol to cementing material on a dry basis ordinarily can be made high enough to insure sufficient access While permitting adequate bonding. The coating procedure may involve dispersion of the phenol in an aqueous film-forming composition which dissolves some or all of the phenol, but the phenol, upon evaporation of the aqueous medium during drying, usually crystallizes out as solid portions which are accessible to the chromogenous material while being bonded to the web. A preferred binder is a natural rubber latex resin. For example, an aqueous. natural rubber latex emulsion con taining 72% resin solids may be used. A coating composition is made by dispersing 15 parts by weight of resorcinol, for example, in parts of the latex emulsion, giving about 1 part of resorcinol to 4 parts of inert bonding material. This composition is coated on a web such as a 16 pound sulfite bond paper, then dried to form a coating approximately 0.0005- inch thick. A wide web may be thus coated, slit, and cut into sheets. Two or more times as much resorcinol can be dispersed in the same amount of latex and successfully coated; moreover, dried coating thicknesses as small as roughly 0.00005 inch or as large as roughly 0.001 inch may be obtained. This permits Wide variations in the effective amount of phenol substance obtained in the coating. A synthetic latex, such as a polybutadiene-styrene latex, may be substituted for the natural rubber latex. Thus it appears that amounts of the phenol in the coating equal to well over 10% of the dry coating weight and within the limits of 0.2 to 8 grams per 1,000 square inches of web surface, as mentioned above, may be obtained readily.

Manifolded sets of the type' including this face-coated web 13 now will be described in greater detail, and particular reference then will. be made to the variety of chromogenous materials suitable for inclusion in the arrangements using the phenolic color-activating substances.

The web or sheet 13 described hereinabove, having on one side an adherent coating 14 carrying a phenolic substanceas described hereinabove, conveniently is included, in an embodiment of the present invention, as the lower or second base Web or sheetin a manifolded set which also comprises the upper or first base web or sheet 11. In this arrangement the first base web 11 has on one side the transfer coating 12 made up of a film-forming material containing a colorless or lightly colored chromogenous compound which is transferable upon impact from that coating to a surface contiguous therewith. This chromo- 9 genous compound includes as its major functional arrangement the molecular structure having a p-amino-substituted triphenylmethane group with a bond from the methane carbon atom thereof to the heterocyclic oxygen atom. It will be understood that substituents may be present on the benzene rings in this compound provided that the illustrated structure remains the effective major functional arrangement in the compound.

The first and second webs 11 and 13 are maintained disposed together in face to face relationship, as suggested by the bracket at the left of the drawing, with their respective transfer and adherent coatings 12 and 14 in contiguity With each other, whereby, upon impact in localized areas, a dark colored material is produced locally by the action of the many small particles of the phenolic substance, carried by the adherent coating 14, in opening the bond from the methane carbon atom to the heterocyclic oxygen atom to permit quinonoid resonance in the small masses of the chromogenous compound which are transferred locally to the contiguous adherent coating from the transfer coating 12 as a result of the impact. For producing simultaneously an original and one copy sheet by use of a typewriter, for example, or by direct writing with pen, pencil, or stylus, the web 11 advantageously serves as the original and the face-coated web 13 serves as the duplicate. These two coated manifolding units 11 and 13 and other pairs like them may be fastened together in successive sets in a pad, or they may simply be laid one over the other on a Writing surface, or held together on the platen of a typewriter. Typing or writing impact, or other printing or marking pressure, on the face of the sheet 11 causes localized rupture of the back coating 12, releasing and transferring some of the chromogenous compound from that coating locally to the contiguous surface of the adherent face coating 14. Of course, it is possible to cause a similar transfer by impact applied to the back of the web 13.

It is possible to incorporate the generally light-colored chromogenous material, of the type described above and in the solid state, into a back coating 12 of waxy or thermoplastic film-forming material, which may be transferred from the base web 11 upon impact to deposit some of the solid chromogenous material on a surface, such as that of the coating 14, carrying a color-activating material. Production of the darker colored form occurs best, however, if the chromogenous substance is dispersed or preferably dissolved in a liquid, permitting intimate contact of the molecules of the chromogenous substance with the color-developing material. It is possible to provide some of this solvent on the surface carrying the color-developing material. Preferably, however, the film-forming material of the back coating 12, which is rupturable upon impact or other localized pressure, contains as a finely dis persed phase numerous cells, or microscopic droplets, of a liquid vehicle carrying the colorless or lightly colored chromogenous compound. The cell walls may be simply boundary regions within the continuous film or may consist of a third encapsulating material. A low vapor pressure, lipophilic (oil-loving), nonpolar or mildly polar liquid solvent vehicle advantageously is used, such as benzyl butyl phthalate, benzyl salicylate, phenyl ether or halogenated phenyl ethers, chlorinated biphenyl, partially hydrogenated terphenyls, lauryl bromide, butyl oleate, or

10 other such vehicles or mixtures thereof, in which the chromogenous compound is dissolved.

A solution of from about 1% to 10% by weight of the chromogenous compound in such a solvent vehicle may be prepared, for example, and then emulsified in a conventional aqueous film-forming material such as polyvinyl alcohol in colloidal solution, or such as a col- 'loidal aqueous solution of casein, gelatin, or the like. The resulting emulsion of the lipophilic solvent in the hydrophilic film former is coated on the back surface of the base web 11, which may be a strip or sheet made of paper or other fibrous material or of a plastic film base, and then is dried to form the coating 12 containing numerous liquid cells of the Water-insoluble solvent vehicle carrying, dissolved therein, the choromogenous substance. Use of a suitable emulsion results in such liquid cells being finely dispersed throughout the solid film, formed by drying the hydrophilic film former, which makes up the continuous phase in the coating 12. The dried coating 12 may be about 0.001 inch thick. The ratio of the solvent vehicle containing the chromogenous compound to the dried film-forming materials in the coating advantageously may be in the approximate range of 1:1 to 1.5:1.

Marking pressure or impact then releases the chromogenou-s material from those of the tiny cells in the coating 12 which occupy the areas immediately beneath the areas of impact on the original printing or writing surface. The above-disclosed phenolic substance in the contiguous coating 14 is adherent to the web 13 but is accessible to materials applied to the surface of this coating, so that adequate contact occurs of the chromogenous compound, transferred from the coating 12, with the phenolic substance, and the dark-colored form of the chromogenous compound thus is produced to provide dark marks in the duplicate image areas on the coating 14.

It will be understood that, if desired, a coating 15 may be formed on the back surface of the duplicate web 13 in just the same manner as the back coating 12 is formed on the original web 11. With this optional back coating 15 on the web 13, one or more additional duplicate coated webs, identical with the coated web 13, may be manifolded beneath the web 13, permitting simultaneous production of triplicate and quadruplicate copies. In fact, most of the phenolic substances utilized in accordance with the present invention, when applied in face coatings such as the coating 14 described above, themselves provide good original printing or Writing surfaces, so that a sheet such as the sheet 13, when provided with the back coating 15 as well as the face coating 14, may serve either as an original sheet or as a duplicate sheet in a manifolded set or stack. Thus identical paper sheets, each having white or light-colored face and back coatings acceptable as ordinary paper surfaces to most users, may be manifolded in sets of two or more, or several sheets may be manifolded in which the face coating may be omitted from the top sheet only and the back coating may be omitted from the bottom sheet only. No smudging or soiling of the paper sheets or of the users hands occurs in ordinary usage, and dark-colored material is formed only in the duplicate image areas by the aforementioned action of the phenolic developer material on the almost colorless or White, or rather lightly colored, chromogenous material.

As already mentioned hereinabove, the manifolding arrangement, which maintains these first and second webs disposed together, may use either of the chromogenous and color-activating materials in the transfer coating and the remaining material in the adherent coating. In either case, upon local impact, rupturing the transfer coating, the release of the liquid vehicle containing one coating constituent from some of the liquid cells onto the contiguous adherent coating carrying the other coating constituent effects contact between the two coating constituents to produce a dark-colored material by the action of the phenolic. substance on the chromogenous compound. The mechanism of this. action need not be demonstrated in showing the operation of the arrangements and methods of the present invention. Nevertheless, it commonly is theorized, in the study of colored substances having an aminotriphenylmethane structure, that absorption or refiection of light selectively in various portions of the visible spectrum is associated with the presence of the quinonoid structure in one of the p-aminophenyl groups,

as may be represented in the structural formula.

l/ N- =N having a double bond from the methane carbon atom to a quinonoid-modified aminophenyl group, and that this quinonoid structure shifts through resonance from one to another of the aminophenyl groups. This structural formula will be recognized as being related to the molecular structure of the major functional arrangement in the chromogenous compound described hereinabove. Presumably contact of the color-activating material with the chromogenous compound results in loss of an electron from the latter, promoting the quinonoid structure having a double bond from an aminophenyl group to the methane car-hon atom, with opening of the bond from the methane carbon atom to the heterocyclic oxygen atom in the chromogenous compound. The precise or complete structure of the dark colored material, produced by the action of a phenolic color-activating material on these chromogenous compounds, is not known, and the hypothetical formula for the quinonoid form, given above, is not intended to be a complete structural representation. Whatever the exact mechanism may be, it seems reasonable in view of the present state of the art to assume that the color-activating substance acts by eifec tively opening a bond from the methane carbon atom with establishment of the double bond arrangement associated with an adjacent quinonoid. group, permitting quinonoid resonance in the chromogenous compound.

Reference now will be made again to the chromogenous compound, before it is acted upon by the coloractivating substance, having the major functional arrangement involving the molecular structure, shown. herein? above, with a p-amino-substituted triphenylmethane group and a heterocyclic ring; the methane carbon atom of the triphenylmethane group has a bond to the hetero oxygen atom, which in turn is bonded to a carbon atomaffixed to one of the phenyl groups in the ortho position. This molecular structure is included with the minimum of substituents in the compound 1,l-bis(p-arninophenyl)- phthalan. The latter compound is represented. by the structuralformula The colorless or lightly colored chromogenous compound preferably is selected from the group consisting of the last-mentioned compound, the 2,2"-epoxy, 3-01-10, and 2,2"-epoxy,-3-oxo derivatives. thereof, bifunctional derivatives of each of these compounds having a second heterocyclic ring fused to the 5,6 side of the benzene nucleus and similarly carrying extracyclic substituents the same as those carried by the carbon atoms designated 1 and 3, the S-amino derivatives of the 1,1-bis(p-aminophenyl) phthalan and of the above-mentioned epoxy and 0x0 derivatives thereof, and N-substituted derivatives of each. of the compounds here listed in which each individual substituent for an amino hydrogen atom is selected from the group consisting of an alkyl radical of not more than four carbon atoms, the henzyl radical, and the phenyl radical.

Each of these compounds can be seen to include as its major functional arrangement the molecular structure set forth hereinabove, with hydrogen atoms or appropriate substituents on the amino nitrogen atoms and on the available heterocyclic carbon atom, and with or without other substituents, such as the epoxy linkage and the third p-amino radical, or such as the bifunctional arrangement involving a second bis(p-amino-phenyl)- methyl group and a second heterocyclic ring fused with the 5,6 side of the benzene nucleus. The N-substituted derivatives of the several compounds listed above are by far the most important members of this group of chromogenous compounds. Examples of the chromogenous substances having particular utility in connection with the present invention will be given now.

Turning first to the l,1.-bis(p-aminophenyl)-phthalan itself, its structural formula may be redrawn as follows:

It maybe used, preferably dissolved in a lipophilic solvent,

to develop a violet color when brought into contact with a phenolic color-activating or developer substance.

However, it is preferred to provide related chromogenous, compounds in which at least one of the two hydrogen atoms in each amino radical is replaced by a substituent' tending to increase the color intensity or modify the hue of the dark-colored material which may be formed from the chromogenous compound. Thus the corresponding N-monosubstituted compound 1,1-bis (p-ethyla-minophenyl')phthalan develops a. greenish blue color of greater intensity, while the N-disubstituted compound l,l-bis(p-dimethylaminophenyl)phthalan forms a still more intensely colored quinonoid form with a green, or somewhat bluish green, hue. The compound 1,1-bis (p-diethylaminophenyl)phthalan produces an intense, green dark-colored form in contact with the phenolic developer substances, and. similar dark-colored forms may be obtained, for example, from similar compounds having diisopropylaminophenyl and dibutylamino-phenyl groups. These compounds illustrate the selection of one or more ofthe individual N-substituents, that is, substituents for the amino hydrogen atoms, from the alkyl radicals of not'more than four carbon atoms. In general, more intenseandmore stable colors may be obtained when there are'substituents replacing most or all of the amino hydrogen atoms. Moreover, instead of these N-alkyl-substituted compounds, the benzyl-substituted compounds 1,1-bis(p-benzylaminophenyl)phthalan and l,l-bis(p-dibeuzylaminophenyl)phthalan may be used to obtain dark greenish blue quinonoid forms. As an exmay be brought into contact with an active phenolic developer material to produce a violet-red or bluish red dark colored form of fair intensity. A deeper, bluish violet-colored substance may be produced from S-amino- 1, 1 -bis p-methylaminophenyl phthalan.

Among the more preferred S-amino derivatives of 1,1- bis(-p-aminophenyDphthalan, however, may be mentioned 5 dimethylamino 1,1 bis(p dimethylaminophenyl) phthalan, forming a bluish violet quinonoid substance. Another N-substitutecl modification of the S-amino derivative is, for example, S-anilino-l,l-bis(p-anilinop henyl) phthalan, which has three N-monophenyl-substituted amino groups and gives greenish blue to blue dark colored quinonoid materials.

It will appear that N-substituted l,1-bis(paminophenyl)phthalan and 6-amino-l,1-bis(p-aminophenyl)- phthalan compounds are particularly desirable for use in systems in which white or light colored chromogenous compounds are converted to dark colored forms. Thus, for such use there may be provided advantageously a colorless or lightly colored chromogenous compound having a modified 1,1-diphenylphthalan structural formula which includes the three points, designated thereon the p,p,5-positions, each para to the position of a bond to the methane carbon atom occupying the 1-position, and which is modified by the inclusion of an amino radical in at least the first-mentioned two of the three p,p',5-positions. Each such amino radical furthermore has at least one substituent selected individually from the group consisting of an alkyl radical of not more than four carbon atoms, the benzyl radical, and the phenyl radical. When the first-mentioned two p,p'-positions carry such amino radicals, the compound is a l,1-bis(p-aminophenyl)- phthalan with one or two substituents for the hydrogen atoms in each amino radical. When all three p,p,5-positions carry such amino radicals, the compound is, of course, an N-substituted S-amino-l,1-bis(p-aminophenyl)- phthalan.

Turning now to the 2,2-epoxy derivative of l,l-bis(paminophenyDphthalan, this derivative without further substituents is 3',6'-diaminospiro (phthalan-1,9'-xanthene) having the structural formula HgN This compound develops a generally red or bluish red color upon contact with various phenolic developers. However, a colorless or lightly colored chromogenous compound is preferred in the form of a substituted 3,6'- diaminospiro(phthalan-l,9'-xanthene) compound, having the structural formula shown just above, in which each of the amino radicals also has at least one substituent selected individually from the group consisting of an alkyl radical of not more than four carbon atoms, the benzyl radical, and the phenyl radical. Accordingly, a more intense bluish red is obtained from the corresponding N-monoalkyl-substituted chromogenous compound 3,6 bis(ethylamino)spira(phthalan 1,9 Xanthene), while a still more intensely colored quinonoid form having a red or somewhat bluish red color may be obtained from the N-dialkyl-substituted compound 3',6'-bis(dimethylamino)spiro(phthalan-l,9 xanthene). The 5- amino-2,2-epoxy derivatives of l,l-bis(p-aminophenyl)- phthalan may be exemplified by the N-substituted compound 3,5,6' tris(dimethylamino)spiro(phthalan 1,9- xanthene), which develops a very intense reddish violet color.

The compounds given in the above examples, having the S-membered heterocyclic ring containing the hetero oxygen atom, may be referred to as cyclic ethers. Compounds of this type, and webs carrying transfer coatings containing such compounds, are disclosed and claimed in the concurrently filed application for Letters Patent of the United States Serial No. 135,307, entitled Chromogen-ous Amino Derivatives of Diphenylphthalan and Marking Method Using Same, filed in the names of John R. Johnson and Earl J. Gosnell and assigned to the same assignee as the present invention.

Such cyclic ether compounds without the epoxy bridge may be prepared by reduction of the corresponding lactones of p-amino-substituted tn'phenylmethanes, namely 3,3 bis(p aminophenyl)phthalide, 6-amino-3,3-bis(paminophenyl)phthalide, and the N-substituted derivatives thereof. Procedures for making these lactones are discussed in US. Patents Nos. 2,417,897, 2,474,084, and 2,597,965 to Adams and No. 2,742,283 to Crounse.

The synthesis of the cyclic ethers from such lactones may be achieved with the use of anhydrous aluminum lithium hydride; for example, about 10 grams of the AlLiH may be refluxed with about 0.025 mole of the appropriate lactone in 350 ml. of ethyl ether for several hours. After adding water, the other layer is decanted and dehydrated, and the ether is evaporated to obtain the solid product, usually having a white or light pastel color. If the solid chromogenous material which has been synthesized is darker than a medium pastel shade, repeated purification treatments using standard procedures, such as solvent or freeze crystallizations and selective solvent extractions, as with ether, can be expected to yield a light-colored product approaching a colorless, that is, white, solid. Such chromogenous substances can be in corporated readily on paper in transfer coatings which appear substantially white or which have a creamy color quite acceptable as an ordinary paper surface.

Synthesis of the cyclic ether compounds with the epoxy bridge, namely the 2,2"-epoxy and -amino-2',2"epoxy derivatives of l,1-bis(p-aminophenyl)phthalan with N- substituents as desired, also may use a lactone as a starting material. Lactones with the epoxy bridge may be formed by reaction, in the presence of ZnCl of phthalic anhydride or 4-aminophthalic anhydride and m-aminophenol, with appropriate substituents for the amino hydrogen atoms in both of these reagents. The aminophenol conveniently may be melted and the other materials dispersed in the melt. The mixture is maintained in molten condition during the reaction period, at the conclusion of which the melt contains in major amount 3',6'-diaminofiuoran having the structural formula with corresponding substituents. Thus, if 4-aminophthalic anhydride is used, the lactone compound has a S-amino group. Similarly, the aforementioned substituents for the hydrogen atoms in the amino groups of both reagents appear as N-substituents in this fluoran product, known in the art as a rhodamine lactone or colorless base. The lactone conveniently may be separated from the crude raaction mixture by digestion in dilute aqueous ammonium hydroxide to dissolve other materials and convert the lactone to solid particles of the corresponding carbinol or color base, which are filtered off, washed, and dried. Refluxing the carbinol in benzene under dehydrating conditions effects recovery of the colorless or lightly colored lactone product shown above in the structural formula for diaminofluoran.

Alternatively the lactone product may be obtained from the commercial rhodamine dye, such as Rhodamine B. The dye, incidentally, may be obtained conventionally by extracting the carbinol or color base, produced as above, with benzene and further extracting the resulting benzene solution with dilute hydrochloric acid, whereupon crystals of the purified dye separate from the aqueous acid solution on cooling. When starting with the dye, the carbinol is regenerated by treatment of an aqueous solution of the dye with sodium hydroxide, extracting, filtering, and drying, followed by the abovementioned refluxing in benzene under dehydrating conditions to close the lactone ring and form the fluoran product.

Refiuxing the substituted 3',6'diaminofluoran, or rhodamine lactone, material thus obtained in anhydrous ether containing aluminum lithium hydride effects reduction to the desired corresponding cyclic ether compound with the epoxy bridge. This substituted 3,6 diaminospiro (phthalan-1,9-xanthene) compound may be termed a rhodamine cyclic ether. Such a reduction procedure is analogous to the reduction of the 3,3-bis(p-aminophenyl) phthalides to their corresponding cyclic ethers utilizing aluminum lithium hydride, as described above. While the rhodamine lactones themselves are chromogenous compounds useful in the production of colored forms in accordance with the present invention, as will be mentioned hereinbelow, the corresponding rhodamine cyclic ethers exhibit considerably greater stability against premature conversion to colored forms and'are considered preferable for use in accordance with the present invention.

Turning next to the 3-oxo derivative of l,l-bis(paminophenyl)phthalan, this compound is a lactone having the structural formula HzN- NH2 20 1 l 4 C O Since more conventional nomenclature treats this compound as a phthalide derivative, namely 3,3-bis(p-amino phenyl)phthalide, the usual numbering of the ring components for phthalide will be used, as shown above. With N-substituents as desired, this is the same phthalide substance already mentioned in connection with the synthesis of the cyclic ethers. The unsubstituted 3,3-bis(paminophenyl)ph-thalide develops a violet color upon intimate contact with a recommended phenolic color-activating substance. A more intense, greenish blue color can be obtained using 3,3-bis(p-methylaminophenyl) phthalide. However, formation of darker quinonoid compounds can be expected from N-tetraalkyl-substituted compounds. Thus a considerably more intense green or somewhat bluish green color is developed using 3,3- bis(p-dimethylaminophenyl)phthalide, which conveniently may be referred to as the lactone of leuco-rnalachite green, and an exceilent dark, intense, bluish green quinonoid form also is produced from 3,3-bis(p-diethylaminophenyl)phthalide. Similarly, a blue-green color is obtained with 3,3-bis(-p dipropylaminophenyl)phthalide. Also quite satisfactory, although not N-alkyl-substituted, is 3,3-bis(p-dibenzylaminophenyl)phthalide, giving a greenish blue colored form.

The 5-amino-3-oxo derivative of 1,1-bis(p-aminophenyl)phthalan, also a lactone, is better named 6- arnino-3,3 bis(p aminophenyl)phthalide, having the structural formula NH: Preparation of this triaminosubstituted 3,3-diphenyl phthalide also is mentioned above. A violet-red or bluish red color may be developed from this compound, as shown without amino substi-tuents. Bluish-violet colors generally are obtained in the quinonoid forms of such compounds which have two or preferably three N-alkyl substituents, such as 6-amino-3,3-bis(p-methylaminophenyl)phthalide and 6 ethylamino 3,3 bis(p ethylaminophenyl)phthalide. However, for the property of rapid production of intense, dark,bluish violet quinonoid forms it is preferred to use N-hexaalkyl-substituted compounds. These are exemplified by 6-dimethylamino-3,3- bis(p-dimethylaminophenyl)phthalide, also identified as crystal violet lactone, and by 6-diethylamino-3,3-bis(pdiethylaminophenyl)phthalide and the same compound with three dipropylamino groups in place of the diethylamino groups. Considered particularly desirable for the production of bluish violet colored forms is 3,3-bis(pdiethylaminophenyl) ,6 dimethylaminophthalide, for which there may be substituted the compound 3,3-bis(pdiisopropylaminophenyl) 6 dimethylaminophthalide. 75- Similar properties also are obtained with n butyl groups,

as in 6 dibutylamino 3,3 bis (p dibutylaminophenyl) phthalide. Again, benzyl and phenyl substituents may be used in place of alkyl substituents. Thus, a different color for the quinonoid form may be obtained from 6- N benzyl N methylamino 3,3 bis(p N benzyl N- methylaminophenyl)phthalide having a red-violet quinonoid form, and the compound 3,3-bis(p-anilinophenyl)- 6-dimethylaminophthalide has a blue dark colored form.

It will appear from the foregoing that the N-substituted 3,3 bis(p aminophenyl)phthalide and 6 amino 3,3- bis(p-aminophenyl)phthalide compounds are preferred for their good chromogenous properties. Such colorless or lightly colored compounds may be defined as chromogenous compounds having a modified 3,3-diphenylphthalide structural formula which includes the three points, designated on the above formula as the p,p',6-positions, each para to the position of a bond to the methane carbon atom occupying the 3-position in this formula, and which is modified by the inclusion of an amino substituent in each of at least the first-mentioned two of the three p,p,6-positions. When those two p,p'-positions have that substituent, the compound is a 3,3-bis(p-aminophenyl)phthalide, and when all three p,p',6-positions have that substituent, the chromogenous compound is in the form of a 6-amino-3,3-bis- (paminophenyl)phthalide. Again, each of the amino radicals in these compounds should have at least one substituent selected individually from the group consisting of an alkyl radical of not more than four carbon atoms, the benzyl radical, and the phenyl radical.

The examples mentioned above indicate that the alkyl groups in these compounds advantageously are methyl, ethyl, n-propyl, and isopropyl groups. A particular preference is noted for the hexaalkyl-triamino-substituted 3,3-diphenylphthalide chromogenous compounds, in the form of 6 dialkylamino 3,3 bis (p dialkylaminophenyl)phthalide compounds in which each individual alkyl radical of the three dialkylamino groups has not more than three carbon atoms.

The 2',2"-epoxy-3-oxo derivative of 1,l-bis(p-aminophenyl)phthalan is 3',6-diaminofluoran having the structural formula which can be used to develop a reddish color with a tinge of blue or violet. The N-substituted derivatives or rhodarnine lactones are preferred, and their synthesis by known procedures is summarized hereinabove. Better color intensity of the quinonoid form is obtained from 3',6-bis(ethylarnino)fiuoran and still deeper color from 3-diethylamino-6-ethylaminofluoran, which is the lactone of Rho'damine 4G, while a preferred chromogenous amino-substituted fiuoran is 3,6-bis(diethylamino)fluoran, the lactone of Rhodamine B; these chromogenous compounds have bluish red quinonoid dark-colored forms. The compound 3,6-dianilinofluoran also is useful and forms a violet dark-colored substance. Compounds which may be viewed as 5-amino-2',2"-epoxy-3-oxo derivatives of l,1-bis( p-aminopheny1)phthalan, in other words 3',5,6'- triaminofiuoran, with N-substituents, also may be obtained, as by the synthesis mentioned above using the reagents 4-aminophthalic anhydride and m-aminophenol with corresponding N-substituents; an example is the chrornogenous compound 3,5,6'-tris(dimethylamino)fluoran, which can form a very intensely colored reddish violet substance. The lactone ring structure present in these aminofluoran compounds has a tendency to open with consequent premature formation of a colored material, and it has been reported that this tendency is fostered in the presence of highly polar solvents such as alcohol, acetone, and water. Accordingly, when these chromogeneous compounds are used, they should be protected against contact with such materials or vapors prior to formation of the desired permanent dark colored forms by contact with the color-activating material on the facecoated sheet in accordance with the invention; or corresponding rhodamine cyclic others may be used.

Coming now to the bir'unctional derivatives of 1,l-bis (p-aminophenyl)phthalan having a second heterocyclic ring fused to the 5,6 side of the benzene nucleus, these derivatives will be seen to be based on the compounds having the structural formula IIIH:

and the isomeric structural formula 11 2 NHg 3 p 0 0 \C/ \C/ H2 H2 -These isomeric compounds may be named respectively l,1,5,5 tetrakis (p-aminophenyl) -7-hydro-1H,3H-benzo- (1,2-c:4,5-c')difuran and 1,1,7,7-tetrakis(p-aminophenyl)-5-hydro-lH,3H-benzo(l,2-c:4,5-c')difuran. Each of these two compounds has two heterocyclic furan rings fused to the central benzene nucleus, and each of these furan rings includes one carbon atom carrying two unsubstituted hydrogen atoms, as may be seen at the bottom of the last structural formula shown above.

The last mentioned carbon atoms may be oXo-substituted; that is, the two hydrogen atoms carried by each carbon atom may be replaced by an oxygen atom. Each furan ring thus assumes a gamma-lactone structure, instead of the cyclic ether structure, giving a bifunctional lactone, or dilactone, compound. The respective dilactone compounds may be named 3,3,7,7-tetrakis(p-aminophenyl) 1H,3H benzo(1,2-c:4,5-c)difuran-l,5(7H)- dione and 3,3,5,5-tetrakis (p-aminophenyl)-1H,3H-benzo (l,2-c:4,5-c) difuran-1,7 (5H)-dione.

Dilactone compounds of the last-mentioned type are disclosed and claimed in the concurrently filed application for Letters Patent of the United States Serial No. 135,264, entitled Chromogenous Aminophenyl Derivatives of Benzodifurandione and Marking Method Using Same, filed in the names of Earl J. Gosnell and John F. Mc- Carthy, Jr., and assigned to the same assignee as the present invention. A representative N-substituted dilactone compound may be synthesized by dissolving one mole of N,N-dimethylaniline in about four times its weight of carbon disulfide and stirring in about 0.9 mole of anhydrous aluminum chloride as a catalyst. After dissolution of the AlCl 0.2 mole of pyromellitic dianhydride is added, stirred, and allowed to stand. The upper layer of the CS is decanted and 1250 ml. of 8% sulfuric acid added to its slowly. After dilution with about 10 liters of water and standing, the first stage of the synthesis gives an approximately 90% yield of a solid intermediate product which is a mixture of two isomeric compounds having the structural formulas where each radical designated X is the .p-dimethylaminophenyl radical derived fromthe N,N-dimethylaniline. In the second stage of the synthesis, a portion of the isomeric intermediate mixture then is heated at reflux temperature for 24 hours, with a further amount of N,N-dimethylaniline equal to about 4.5 to 5 times the equimolar weight, in a volume of liquid acetic anhydride weighing about 7 to 8 times as much as the Weight of the N-substituted aniline. Cooling and filtering gives a solid acetic anhydride insoluble product of light yellow color, and pouring the filtrate over crushed ice and filtering gives a solid acetic anhydride-soluble product of light greenish yellow color, both in good yields. A mixture of these two solid products may be-obtained by flushing with ice water before filtering out the acetic .anhydride-insoluble fraction.

These two light-colored products are the chromogenous substances selected from the group consisting of the isomeric compounds having the structural formulas where X is 'as above and the radical designated X also is the p-dimethylaminophenyl 'r'adic'al, derived in this instance from the dimethylaniline used in the reaction with the intermediate mixture. It will be appreciated that aniline itself, or other N-subst-ituted anilines, may be used in forming the intermediate mixture with corresponding variations in the p-aminophenyl radical X, while aniline, or still another bl-substituted aniline, may be used as the reagent with the intermediate isomers to get the dilactone product with other corresponding variations in the p-aminophenyl radicalX. Yields of the acetic-anhydride-insoluble and -soluble fractions vary, and standard purification procedures such as solvent or freeze crystallizations and selective solvent extractions can be utilized Where necessary to recover-crystalline products having substantially colorless creamy or light pastel shades. The dilactones generally can be heated well above 300 C. without melting or decomposition.

The synthesis of a specific chromogenous dilactone compound, or isomeric mixture of such compounds, having the structure represented by the formulas given above where all of the radicals designatedboth X and X are p-dirnethylaminophenyl groups, is mentioned hereinabove by way of example. The two-isomeric fractions have very low solubilities in most of the common organic solvents. However, they dissolve up to a few percent or more in some of the solvent vehicles such as the simple or chlorinated phenyl ethers and chlorinated polyphenyls,

2% and the solution of either one or both of the above-mentioned fractions gives instantaneously a dark blue-green colored form when brought into contact with one of the phenolic substances listed hereinabove.

Indicating the variety of dilactone chromogenous compounds which can be utilized in accordance with the present invention, the use of unsubstituted aniline in the synthesis described above gives the tetrakis(p-aminophenyl) benzodifurandione or dilactone substance without N-substituents, X and X both being p-aminophenyl radicals, and contact with developers yields a reddish or purplish tan colored form. It is much preferred, however, to use substituted anilines, particularly N,N-disubstituted anilines. Thus the N,N-dimethylaniline advantageously is used in many cases to make the intermediate product having the p-dimethylaminophenyl group for the radical X. However, appropriate variations in the substituted aniline reacted with the intermediate product in the second stage of the synthesis described above yield dilactone products in which the radical X consists of different N-substituted p-aminophenyl groups, preferably other N-dialkyl-substituted groups with alkyl radicals of not over three carbon atoms. X accordingly may be the p-diisopropylaminophenyl radical, while X remans the p-dimethylaminophenyl radical. This dilactone substance also gives a dark blue-green quinonoid form 'on contact with a phenolic develo'per material. Blue-green forms also are obtained from the dilactone in which X is thep-N-benzyl-N-ethylaminophenyl group, while the dilactone in which X is the p-dibenzylaminophenyl.group .gives a bluish green to green dark colored form. Corresponding andsometimes superior results can beobtained'with halo or methylsubstituentsion the phenyl ring in the p-aminophenyl radical. Thus, when m-choloro-N,N-diethylaniline is used in the second stage of the synthesis, the resulting dilactonezprodnot has o-chloro p'diethyla minophenyl groups for the X radicals, X still remaining .the p-dirnethylaminophenyl group. This substance gives a green dark-colored form.

- 0 o o o o o o 0 including, fused to opposite sides of the benzene nucleus,

two heterocyclic rings each containing a hetero oxygenatomin the ring, and to each of which two other oxygen atoms are attached. One of these two oxygen atoms attached to each-hetero'cyclic ring thereof is replaced by two p-dialkylaminophenyl groups, in which each individual one of the four alkyl radicals has not more than three carbon atoms.

Instead of a dilacetone substance, there may be used the corresponding bifunctional cyclic ethers, which are the usually N-substitutedderivatives of the l,l,5,5-tetrakis (p-aminophenyl)-7-hydro-1H,3H-benzo(1,2 c:4,5-c)- difuran and of its isomer, shown above. To produce the bifunctional cyclic ethers, or dicyclic ethers, appropriate dilactones, such as those just mentioned, may be added to ethyl ether which is maintained at reflux temperature and which contains aluminum lithium hydride, and the bifunctional cyclic ether recovered by filtration and solvent evaporation. These products after purification have chromogenous characteristics similar to those of the corresponding dilactone materials, having the same N-sub-stituted p-aminophenyl groups represented by the radicals X and X in the structural formulas shown above.

In addition to such bifunctional cyclic ethers, and the bifunctional lactones, or dilactones, already described, the corresponding bifunctional derivatives of l,l-bis(paminophenyl)phthalan having the epoxy bridges also may be used. In this category the diepoxy-substituted dilactones have the isometric structural formulas NHz and

O O I I I r l 0 o o o and the amino hydrogen atoms again preferably are replaced by alkyl, benzyl, or phenyl radicals. Thus all of the amino groups may be dialkylamino groups in which each alkyl radical has no more than three carbon atoms, e.g., dirnethylarnino groups or diethylamino groups.

As an example, the isomeric sus'otance having diethylamino groups may be obtained by heating one mole of m-diethylaminophenol and roughly one mole of anhyo drous zinc chloride with 0.2 mole of pyromellitic dianhydride.

O O 0 0 o o C C O O for several hours at 160 C. while stirring the melt, to form in the melt a moderate yield of a bifunctional compound including the structure lTHCaHs):

. 22 It will be seen that the portion of the molecular structure illustrated here is the lactone of Rhodamine B, that is 3,6'-bis(diethylamin-o)fiuoran. It will be understood further that the pyromellitic dianhy-dride acquires a simi lar Spiro-linked Xanthene structure, not illustrated here, on the other side of the benzene nucleus, where another one of the dianhydride carbonyl oxygen atoms is replaced with two more aminophenyl radicals. Thus a third mole cule of water is split off, formed from this oxygen atom and the hydrogen atoms in the 6-positions on two additional 3-diethylaminophenol molecules. A second xanthene epoxy bridge also is formed by removal of a fourth water molecule from the two adjacent phenolic hydroxyl groups in these two additional aminophenol molecules.

' To recover this product from the reaction mixture, a procedure related to that indicated hereinabove in connection with production of the familiarrhodamine lac-. tones then may be followed. Thus the melt, containing the reaction product formed from the pyromellitic dianhydride and the 3'-diethylaminophcnol, may be cooled,

finely powdered, and digested with dilute aqueous 'ammonium'hydroxide, leaving undissolved the bifunctional carbinol This substance is separated by filtering it out of the ammonium hydroxide solution, washing with fresh dilute ammonium hydroxide, and drying. Reclosure of the two lactone rings is accomplished by refluxing the carbinol with benzene, which conveniently is done with a standard condenser and Stark and Dean tube apparatus to remove the water split olf from the carbinol hydroxyl groups and the adjacent carboxyl hydrogen atoms. The resulting benzene solution is then filtered and evaporated under vacuum to recover the bifunctional rhodamine lactone substance, whose structure is illustrated by the isomeric formulas shown above, all the amino hydrogen atoms be ing replaced by ethyl radicals in this example.

This product is more or less colorless, having a creamy to light pink color. By using other N-substituted mor 3-aminophenols, a variety of other chromogenous rhodamine dilactone compounds, having different N-substituents and also only lightly colored, may be prepared, as will be understood from a consideration of the various N-substituted dilactone compounds discussed hereinabove, which are the corresponding bifunctional lactones without the epoxy bridges. The colored forms of these rhodamine dilactone substances resemble in hue the colored forms of the corresponding rhodamine lactones, giving generally bluish red colors. However, the rhodamine dilactone substances share with the monofunctional rhodamine lactone compounds a tendency toward premature opening of the lactone rings, which may cause coloration of the chromogenous material before marking contact has been effected with the desired color-activating material. Of course, the rhodamine dilactone substance may be protected from premature contact with atmospheric or other environments which permit premature coloring.

However, it may be preferable to convert the rhodamine dilactones to the corresponding bifunctional cyclic ether substances, which have considerably more stability against adventitious color formation as when exposed to a humid atmosphere. Such bifunctional cyclic ether substances include the structure with suitable N-substituents. Each monofunctional molecular arrangement in this category of bifunctional sub stances will be seen to include the structure of- 3',6'-diaminospiro(.phthalan-l,9'-xanthene)', as illustrated here.-

These bifunctional cyclic ether substances likewise may have either, or a mixture of both, of the isomeric forms corresponding to the two isomeric structural formulas given above for the rhodamine dilactone substances. Any

two isomeric compounds of this structure give very s'imilar colored forms, which also are similar in hue to the colored forms produced from the corresponding rhodamine dilactone and rhodamine lactone substances, although with some-N-substituents minor differences in hue may be observed, even between isomeric pairs, depending on the color-activating substance used.

All of the bifunctional substances in the categories of bifunctional lactones, cyclic ethers, rhodamine lactones, and rhodamine cyclic ethers have high melting points and generally can be heated above 300 C. in a neutral atmosphere without melting or decomposing. Several nonpolar or mildly polar solvents may have to be tried in order to find one which will dissolve several percent or more of these bifunctional chromogenous substances.

The bifunctional rhodamine cyclic ethers, having the functional arrangement illustrated above, are obtained by reduction of the corresponding chromogenous rhodamine dilactone substances, using either of the isomeric forms thereof or a mixture of such forms. The rhodamine'dilactone is stirred slowly into a semidissolved mixture of aluminum lithium hydride in anhydrous ethyl ether. The resulting mixture is refluxed to permit reaction, cooled, and water is added dropwise. The ether layer is decanted, dried with a solid desiccant such as anhydrous sodium sulfate, and the ether evaporated to obtain the chromogenous, substantially colorless or light pink, solid rhodamine dicyclic ether susbtance.

The chromogenous bifunctioual compounds comprising. the dicyclic ethers reduced from dilactone substances, the rhodamine dilactone substances with the epoxy bridges, and the bifunctional rhodamine dicyclic ethers prepared therefrom as just described, are disclosed and claimed in a concurrently filed application for Letters Patent of the United States, Serial No. 135,359, entitled Chromogenous Tetrakis(Aminophenyl) Derivatives of Benzodifuran and Marking Method Using Same, filed in the name of Earl J. Gosnell and assigned to the assignee of the present invention.

All of the monofunctional and bifunction'al chromogenous compounds described hereinabove have a bis(paminophenyl)methyl group, or a 3,6-diamino-9-Xyanthenyl group, with an additional linkage from the methyl carbon atom in the former, or from the carbon atom designated 9 in the latter, to the hetero oxygen atom. Some of the monofunctional compounds have a third amino radical, on the benzene nucleus one side of which is in the heterocyclic ring. In the preferred chromogenous componds these amino radicals have substituents, for which the methyl and ethyl N-substituents are chosen frequently. Propyl and butyl substituents for one or both of the amino hydrogen atoms provide quite similar properties, so that alkyl radicals of not more than four carbon 24 atoms are suitable. Examples of N-benzyl-and N-phenyl groups also appear hereinabove.

Equivalent results also may be obtained, for example, with certain saturated monoalkyl radicals having five carbon atoms or with the mono-n-hexyl radical as N-substituents, and N-substituted cycloalkyl groups such as the cyclopropyl and cyclohexyl groups may be present, but these N-substituents are not preferred. As further examples, the N-phenyl-substituted compounds may be modified by including naphthyl radicals instead of phenyl radicals as N-substituents, or certain small additional substituents may be included on the N-substituted radicals mentioned above, and generally equivalent properties still will be obtained; in this connection such N-subs'tituted groups as the chloromethyl, hydroxyalkyl (e.g., beta-hydroxyethyl, gamma-hydroxypropyl, or delta-hydroxybutyl), sulfophenyl, tolyl, or one of the methylbenzyl radicals may be mentioned. Equivalent to the aminophenyl groups themselves in some chromogenous compounds are amino-l-naphthyl groups; thus 4-diethylamino-1-naphthyl groups may replace p-diethylam'inophenyl groups. Instead of N-substituted amino groups, equivalent results also may be expected with piperidino groups, or an entire N-substituted p-aminophenyl group may be replaced by the 9-julolidyl radical mo 5N It will be appreciated likewise that substantially equivalent properties also are obtainable in the chromogenous compounds when one small substituent or several small substituents, notably one or more methyl, chloro, bromo, fluoro, or nitro radicals, is or are substituted for one or more of the available hydrogen atoms on the phenyl rings in the aminophenyl radicals or on the benzene nucleus one side of which is in the heterocyclic ring.

It should be noted that the choice of one of the phenolic materials disclosed herein as the color-activating material to be used with a particular chromogenous substance, or the choice of the chromogenous substance to be used together with-a particular phenolic material, may require the exercise of the good judgment of one experienced in the art, and in some instances a little experimentation, to arrive at an effective or reasonably satisfactory combination of materials for a specific system. Certain combinations of such phenolic substances and chromogenous substances naturally give the best results in terms of rapid development of very dark and intense colored forms upon ordinary contact of the two substances. The same chr0- mogenous substance can produce dark-colored forms having noticeably different color responses or hues when brought into contact with different ones of the phenolic materials useful as color-activating substances, and the color intensity of the colored forms produced in a given system or arrangement can show gross variations when different phenolic materials are used. The colors given hereinabove for the dark-colored or quinonoid forms of certain chromogenous substances are examples of the colors ordinarily obtained when quite active color-developing phenolic compounds are used. While the phenolic materials useful in accordance with the present invention produce dark colored forms of useful intensities after being brought into ordinary contact with many chromogenous materials, the use of a few of the phenols discussed hereinabove which exhibit somewhat lower activity as color developers than the best of these coloractivating substances may require the application of heat, or the use of other means of obtaining more intimate contact with the chromogenous compound, to cause reasonably good color development. This might be accomplished, for example, by concentrated infrared irradiation or by conductive contact with a hot surface. Such measures might be indicated when using a chromogenous compound giving one of the less intensely colored quinonoid forms, especially when a phenol substance having only moderate activity as a color developer is to be used. It has been found desirable to try a number of solvent liquids for the chromogenous compound to obtain the concentration and other environmental conditions which favor the eificient formation of a dark colored material with desirable color intensity and hue.

The chemical structure of the dark colored forms produced from the chromogenous compounds by the action of a phenol substance has not been established, and accurate analytical methods for providing dependable and incontrovertible evidence of their chemical structure apparently are not available. It is presumed, however, that the phenol or some substantial residue thereof remains bonded or associated with the colored form to which the chromogenous compound is converted, since the colored materials differ, in improved resistance to moisture and other characteristics, from the colored materials produced with inorganic color-developing materials. Accordingly there is provided a new composition of matter, comprising the dark colored substance obtained by intimate contact ofv a phenolic substance, preferably phenol itself, resorcinol, naphthol, or pyrocatechol, with one of the colorless or lightly colored chromogenous compounds. These new compositions may be classified as novel dyestuffs which in most cases are spirit-soluble and oil-soluble.

When these dark-colored materials are formed, the method is being carried out, embodying an aspect of the present invention, in which dark colored materials are developed from chromogenous compounds by bringing a colorless or lightly colored chromogenous compound, which includes as its major functional arrangement the molecular structure into reaction contact with a substance selected from the group of phenol substances listed above. It will appear from the above that marking or printing may be accomplished, without the use of conventional inks containing dark pigments or colored dyes, by using instead of such inks an oily ink vehicle in which the chromogenous compound is dissolved. For letterpress printing, by way of example, the resulting oily vehicle is. applied to the type, which then is impressed on a web surface having a coating containing the phenolic substance. Alternatively, sheets having such a face coating may be used in a typewriter, which is supplied with a ribbon impregnated with an oily ribbon-inking vehicle containing one of the chromogenous substances in solution. Neither the ribbon so impregnated nor the face-coated sheets will soil the fingers or clothing.

Such arrangements illustrate the method of the invention involving, more specifically, the marking on a substrate by developing dark-colored materials from chromogenous compounds, in which one of the chromogenous compounds specified above is provided, preferably dissolved in an oily vehicle, and is brought into contact, in areas on the substrate where mar-king is desired, with the phenolic compound to produce marks in such areas of the dark colored product formed from the two compounds. In the illustration just given, the phenolic colordeveloping material has been applied to the web, sheet, or other substrate prior to use. It will be understood that the chromogenous material might be brought into contact with the phenolic developer in many other ways, some being suggested hereinabove, whether or not the chromogenous material actually is moved to effect the contact. To give another illustration, the chromogenous material may be cemented in solid form on a paper web, using for example a starch binder, and the necessary contact then may be effected through the application of small quantities of phenol itself, in impure form and liquefied at room temperature by adding small amounts of water, to the surface coating in the form of liquid droplets where dark-colored marks are desired. The marking method may be carried out by the use of the manifolded sets described hereinaboye. Any of the 1,1-bis(p-aminophenyl)-phthalan derivatives may be used as the chromog enous compound, the N-substituted 3,3-bis(p-aminophenyDph-thalides and 6-amino-3,3-bis(p-aminophenyl)phthalides often being preferred, although N-suostituted S-am-ino1,'1- bis(p-aminophenyl)phthalan, or 3,6'-diaminospiro(phthalan-1,9'-xanthene), or one of the dilactone substances also usually is particularly suitable for the purpose. Among the most active of the phenol substances in such systems are phenol, resorcinol, and either of the naphthols.

Use of the colondeveloping substances provided in accordance with the present invention in modified spiritduplicating systems is attractive. Two colorless or lightly colored substances are provided in this duplicating method embodiment of the invention, one of these two substances being a chromogenous compound as specified herein, and the other of the two substances being one of the phenolic substances. Deposits are formed, on the surface of a master sheet, of a preselected one of these two substances in areas representing an image to be duplicated but with mirror-reversed image elements. These deposits should contain the chromogenous or phenol material in a binder which is insoluble in the duplicating fluid to be used, the fluid being solvent for the aforesaid preselected material to be transferred but not for its binder.

There is more than one way to use the spirit-transfer principle to obtain many duplicate copies from this master sheet. In one variation of this duplicatng method, a solution of the remaining one of the two substances in a solvent liquid is applied to the surface of each duplicate sheet in sequence. The duplicate sheet surface, wetted with the solvent liquid containing the remaining one of the two substances, is pressed against the master sheet surface to effect transfer by the solvent liquid portions of the deposits of the preselected one of the two substances from the master sheet surface to the duplicate sheet surface on the areas of the latter which represent the image. By this procedure a duplicate image is formed, on the duplicate sheet surface, of dark colored material produced by the action of the phenolic substance on the chromogenous compound.

This method may be carried out by forming a reversed image of deposits of the phenolic substance on the master sheet, and then wetting the duplicate sheets with a solvent liquid containing the chromogenous compound. However, it is preferred to use the chromogenous material for making the image-representing deposits on the master sheet. The reverse image conveniently can be formed using transfer sheets or ribbons carrying the chromogenous compound. The transfer coatings may consist of the chromogenous material dispersed in a binder of wax or a paraffin oil, or transfer ribbons may be impregnated with the chromogenous material dispersed in a paraffin oil. Such a transfer sheet may be placed in a typewriter beneath the master sheet with the transfer coating facing the master sheet. Typing then causes a reverse image to be formed of the chromogenous material transferred to the lower master sheet surface, opposite the surface struck by the types. The duplicate sheets then are wetted with a solvent liquid in which the phenolic developer substance is dissolved, whereby a duplicate image is formed, on the duplicate sheet surface, of dark colored material produced by the action of the phenolic substance in the solvent liquid on the portions of the chromogenous compound transferred by the solvent liquid from the master sheet surface to the duplicate sheet surface. The solvent liquid may be, for example, acetone, toluene, benzene, or Z-butanone (methyl ethyl ketone). The solvent liquid and the binder used for the deposits on the master :sheet are chosen so that the binder is not dissolved during successive transfers of portions of the 'chromogenous ma terial from the master sheet to the duplicate sheets.

In another variation, a predetermined one off thetwo colorless or lightly colored substances again is used to form the deposits representing the 'reV'ersed'ir'na'geonthe master sheet surface. The procedure is varied, however, by arranging the remaining .one of the two substances to be carried on at least one surface of the duplicate sheets, usually as a thin coating of the solid substance in a small amount of an adhesive binder. 'The'nalliquid which is a solvent for the preselected one of the .t-wo su'bstances is applied to thatsur'face of the duplicate sheet. The duplicate sheet surface, thus wetted with the solvent liquid, is pressed against the master .she'et surface tocause portions of the preselected one of the two substances deposited thereon to dissolve inthe liquidand toi'be transferred into contact with the remainingone .of the .two substances, carried on the duplicate sheet surface, in the areas representing the image. By this procedure a duplicate image again is formed, on the duplicate sheet surface, of dark colored material formed from the two substances.

'In the duplicating method just described, the preselected substance may =be the chromogenous compound, in which case the remaining substance, which .is the phenolic substance, is carried .on each duplicate sheet. Under certain circumstances, however, it may prove .to be more feasible to pick the phenol compound zinstead as the preselected substance. In preparing the master sheet, the phenol compound .then .is transferred in a binder to the master sheet surface in the configuration of the reversed image, and the chromogenous compound is carried on the active surface ofeach duplicate zsheet. Solvent spirits for the phenolic:substance are used, .such as one of the solvents mentioned above which does not affect the binder for the phenolic deposits. -W=hen 'the duplicate sheet surface is wetted with this solvent liquid and pressed against the master sheet surface, portions of the image-representing deposits of the phenolic substance thereon dissolve intheliquidand are transferred into contact with the chrom-ogenouscompound carried on the duplicate sheet surface, causing the dark-colored material to form in the areas on the-duplicate sheet. surface representing the image to be duplicated.

It appears from the discussionhereinahove that highly useful dark-colored marking materials or dyes are ;.produced, in accordance with the invention, by the action of the phenolic substances on suitable chromogenous compounds, the latter being exemplified by the :bis(paminophenyl)phthalan, triphenylmethane lactones, :and colorless rhodamine base compounds. As compared "with the dark forms produced from the lactones by the action of inorganic developer materials, r :by the action of weak acids such as acetic acid and tartaric acid, these new dark colors are more .permanent in nature, .and;have increased resistance to fading under ultraviolet radiation and to loss of color in the ,presence .of moisture, and greater color intensity.

While there have been described what at present are considered to be the preferred'embodiments of thisinvention, it will be obvious to those .skilled in the art that various changes and modifications :may be .made therein without departing from the invention. -It is aimed, therefor, in the appended claims to cover'all such 28 changes and modifications which .fall within the true spiritand scope of the invention.

What is claimed is:

1. A manifolded set, comprising: a first base web having on one side a transfer coating made up of a film-forming material which is rupturable upon impact and which contains as a finely dispersed phase numerous cells of a solvent liquid vehicle; a second base web having on one side an adherent coating, said first and second webs being maintained disposed together in face to face relationship with said respective transfer and adherentcoatings in contiguity with each other; one coating constituent in the form of a colorless or lightly colored chromogenous compound which includes as its major functional arrangement the molecular structure having a 'triphenylmethane 'group'with a bond :from the methane carbon atom thereof to the heterocyclic oxygen atom; "and another coating constituent in the form of a substance selected from the group consisting 'of phenol, resorcinol, pyr-ocatechol,-quinol, phloroglucinol, pyrogallol, hydroxyquinol, l-naphthol, and Z-naphthol; one of said coating constituents being dissolved in said solvent liquid vehicle present as said numerous cells in the transfer coating on said first base web, and the other of said coating'constituents being bonded to said second web in said adherent coating thereon but being accessible to other materials coming into contact with portions of the adherent coating; whereby, upon local impact and rupture of said transfer coating, releasing said liquid vehicle containing said one coating constituent from some of said cells onto said contiguous adherent coating, contact is effected between said two coating constituents to produce a dark colored material-by the action of said substance in opening said bond from the methane carbon atom to the heterocyclic oxygen atom to permit quinonoid resonance in said chromogenous compound.

2. A manifolded set, comprising: a first base web having on one side a transfer coating containing a colorless or lightly colored chromogeno'us compound which is trans .ferable upon impact from said coating to a surface contiguous therewith and which includes as its major functional arrangement the molecular structure having a triphenylmethane group with a bond from the methane carbon atom thereof to the heterocyclic-oxygen atom; and Tasecond base web carrying on atleast one active surface a substance selected from the group cantsisting of phenol, resorcinol, pyrocatechol, quinol,"phloroglucinol, pyrogallol, hydroxyquinol, l-na'phthol, and '2- naph-thol; said first and second webs being maintained disposed together in face to face relationship with said transfer coating in contiguity with said active surface, whereby, upon said impact in localized areas, a dark 7 2,9 colored material is produced locally by the action of said substance carried on said active surface in opening said bond from the methane carbon atom to the heterocyclic oxygen atom to permit quinonoid resonance in said chromogenous com-pound transferred to said active surface.

3. A manifolded set, comprising: a first base web having on one side a transfer coating made up of a film-forming material which is rupturable upon impact and which contains as a finely dispersed phase numerous cells of a liquid vehicle, carrying a colorless or lightly colored chromogenous compound selected from the group consisting of 1,1-bis(p-aminophenyl)phthalan having the structural formula Harv-A .fiqvm ,1 I y i 2O 73/ o I H2 the 2,2-epoxy, 3 -oxo, and 2',2"-epoxy-3-oxo derivatives thereof, bifunctional derivatives of each of said compounds having a second heterocyclic ring fused to the 5,6 side of the benzene nucleus and similarly carrying extracyclic substituents the same as those carried by the carbon atoms designated 1 and 3, the S-amino derivatives of said 1,l-bis(p-arninophenyDphthalan and of said epoxy and oxo derivatives thereof, and N-substituted derivatives of each of said compounds in which each individual substituent for an amino hydrogen atom is selected from the group consisting of an alkyl radical of not more than four carbonatorns, the benzyl radical, and the phenyl radical; and a second base web carrying on at least one active surface a substance selected from the group consisting of phenol, resorcinol, pyrocatechol, quinol, phloroglucinol, pyrogallol, hydroxyquinol, l-naplithol, and Z-naphthol; said first and second webs being maintained disposed together in face to face relationship with said transfer coating in contiguity with said active surface, whereby, upon local impact and rupture of said transfer coating, releasing said liquid vehicle from some ofsaid cells onto said active surface carrying the substance selectedfrom said group, a dark colored material is produced locally by the action of said substance on the chromog enous compound carried by said liquid vehicle.

4. A manifolded set, comprising: a first base web having on one side a transfer coating made up of a film-forming material which is rupturable upon impact and which contains as a finely dispersed phase numerous cells of a liquid vehicle carrying a colorless or lightly colored chroinogenous compound having a modified 3,3-diphenyl- 'phthalicle structural formula which includes the three points, designated thereon the p,p,6-positions, each para to the position of a bond to the methane carbon atom occupying the 3-position, and which is modified'by the inclusion of an amino radical in 30 each of at least the first-mentioned two of said three p,p', 6-positions, each such amino radical having at least one substituent selected individually from the group consisting of an alkyl radical of not more than four carbon atoms, the benzyl radical, and the phenyl radical; and a second base web carrying on at least one active surface a substance selected from the group consisting of phenol, resorcinol, pyrocatechol, quinol, phloroglucinol, pyrogallol, hydroxyquinol, l-naphthol, and 2-naphthol; said first and second webs being maintained disposed together in face to face relationship with said transfer coating in contiguity with said active surface, whereby, upon local impact and rupture of said transfer coating, releasing said liquid vehicle from some of said cells onto said active surface carrying the substance selected from said group, a

dark colored material is produced locally by the action having a triphenylmethane group with a bond from the methane carbon atom thereof to the heterocyclic oxygen atom; and bringing said chromogenous compound into contact, in areas on said substrate where marking is desired, with a substance selected from the group consisting of phenol, resorcinol, pyrocatechol, quinol, phloroglucinol, pyrogallol, hydroxquinol, l-naphthol, and 2-naphthol, to produce marks in said areas of a dark colored material formed by the action of said substance in opening said bond from the methane carbon atom to the heterocyclic oxygen atom to permit quinonoid resonance in the chromogenous compound.

6. The method of marking on a substrate by developing dark colored materials from chromogenous compounds, comprising: providing a'colorlessor lightly colored chr0- mogenous compound selected from the group consisting of 1,l-bis(p-aminopheuyDphtha-lan having the structural formula the 2', 2"-epoxy, 3-oxo, and 2', 2"-epoxy-3-oxo derivatives thereof, bifunctional derivatives of each of said com pounds having a second heterocyclic ring dividual substituent for an amino hydrogen atom is selected from the group consisting of alkyl radicals of not more than four carbon atoms, the benzyl radical, and the phenyl radical; and bringing said chromogenous compound into contact, in areas on said substrate where marking is desired, with a substance selected from the group consisting of phenol, resorcinol, pyrocatechol, quinol, phloroglucinol, pyrogallol, hydroxyquinol, l-naphthol, and 2-naphthol to produce marks in said areas of a dark colored material formed by the action of said substance on said chromogenous compound.

7. The method of marking on a substrate by developing dark colored materials from chromogenous compounds, comprising: providing a colorless or lightly colored chromogenous compound having a modified 3,3-diphenylphthalide structural formula which includes the three points, designated thereon the p,p,6-positions, each para to the position of a bond to the methane carbon atom occupying the 3-position, and which is modified by the inclusion of an amino radical in each of at least the first-mentioned two of said three p,p',6-positions, each such amino radical having at least one substituent selected individuafly from the group consisting of an alkyl radical of not more than four carbon atoms, the benzyl radical, and the phenyl radical; and bringing said chromogenous compound into contact, in areas on said substrate where marking is desired, with a substance selected from the group consisting of phenol, resorcinol, pyrocatechol, quinol, phloroglucinol. pyrogallol, hydroxyquinol, l-naphthol, and Z-naphthol to produce marks in said areas of a dark colored material formed by the action of said substance on said chromogenous compound.

8. The method of marking on a substrate by developing dark colored materials from chromogenous compounds, comprising: providing a colorless or lightly colored chromogenous compound having a modified 3,3-diphenylphthalide structural formula which includes the three points, designated thereon the p,p,6-positions, each para to the position of a bond to the methane carbon atom occupying the 3-position, and which is modified by the inclusion of an amino radical in each of at least the first-mentioned two of said three p,p,6-positions, each such amino radical having at least one substituent selected individually from the group consisting of an alkyl radical of not more than four carbon atoms, the benzyl radical, and the phenyl radical; and bringing said chromogenous compound into contact, in areas on said substrate where marking is desired, with phenol to produce marks in said areas of a dark colored material formed by the action of said phenol on said chromogenous compound.

9. The method of marking on a substrate by developing dark col ed llfilfiials from chromogenous com- 32 pounds, comprising: providing a colorless or lightly colored chromogenous compound having a modified 3,3diphenylphthalide structural formula 5 p m 3/\/ I l5 7 1r which includes the three points, designated thereon the p,p,6-positions, each para to the position of a bond to the methane carbon atom occupying the 3-position, and which is modified by the inclusion of an amino radical in each of at least the first-mentioned two of said three p,p',6-positions, each such amino radical having at least one substituent selected individually from the group consisting of an alkyl radical of not more than four carbon atoms, the benzyl radical, and the phenyl radical; and bringing said chromogenous compound into contact, in 2 areas on said substrate where marking is desired, with resorcinol to produce marks in said areas of a dark colored material. formed by the action of said resorcinol on said chromogenous compound.

10. The method of marking on a substrate by developing dark colored materials from chromogenous compounds, comprising: providing a colorless or lightly colored chromogenous compound having a modified 3,3-diphenylphthalide structural formula which includes the three points, designated thereon the p,p,6-positions, each para to the position of, a bond to the methane carbon atom occupying the 3-position, and which is modified by the inclusion of an amino radical in each of at least the first-mentioned two of said three p,p',6-positions, each such amino radical having at least one substituent selected individually from the group consisting of an alkyl radicalof not more than four carbon atoms, the benzyl radical, and the phenyl radical; and bringing said chromogenous compound into contact, in areas on said substrate where marking is desired, with naphthol to produce marks in said areas of a dark colored material formed by the action of said naphthol on said chromogenous compound.

11. The method of marking on a substrate by developing dark colored materials from chromogenous compounds, comprising: bringing a colorless or lightly 1colored chromogenous compound which includes as its major functional arrangement the molecular structure H\ /H N N 6;)

W H I/ x O O into contact, in areas Where making is desired, with the surface of a web carrying, evenly distributed in amounts of from 0.2 to 8 grams per 1,000 square inches of web surface, a substance selected from the group consisting of phenol, resorcinol, pyrocatechol, quinol, phloroglucinol, pyrogallol, hydroxyquinol, l-naphthol, and 2-naphthol, to produce marks in said areas of a dark colored material formed by the action of said substance on said chromogenous compound.

12. The method of duplicating, comprising: providing two colorless or lightly colored substances, one of these two substances being a chromogenous compound which includes as its major functional arrangement the molecular structure having a triphenylmethane group with a bond from the methane carbon atom thereof to the heterocyclic oxygen atom, and the other of said two substances being a phenolic substance selected from the group consisting of phenol, resorcinol, pyrocatechol, quinol, phloroglucinol, pyrogallol, hydroxyquinol, l-naphthol, and 2-naphthol; forming on the surface of a master sheet deposits of a preselected one of said two substances in areas representing an image to be duplicated but with mirror-reversed image elements; applying a solution of the remaining one of said two substances in a solvent liquid to the surface of a duplicate sheet; and pressing said duplicate sheet surface, wetted with the solvent liquid containing said remaining one of the two substances, against said master sheet surface to effect transfer by the solvent liquid of portions of said deposits of said preselected one of the two substances from the master sheet surface to the duplicate sheet surface in areas thereon representing said image, whereby a duplicate image is formed on said duplicate sheet surface of dark colored material produced by the action of said phenolic substance in opening said bond from the methane carbon atom to the heterocyclic oxygen atom to permit quinonoid resonance in said chromogenous compound.

13. The method of duplicating, comprising: forming on the surface of a master sheet, in areas representing an image to be duplicated but with mirror-reversed image elements, deposits of a colorless or lightly colored chromogenous compound which includes as its major functional arrangement the molecular structure having a triphenylmethane group with a bond from the methane carbon atom to the heterocyclic oxygen atom; applying to the surface of a duplicate sheet a solvent liquid which carries dissolved therein a phenolic substance selected from the group consisting of phenol, resorcinol, pyrocatechol, quinol, phloroglucinol, pyrogallol, hydroxyquinol, l-napthol, and Z-naphthol; and pressing said duplicate sheet surface, wetted with the solvent liquid, against said master sheet surface to effect transfer by the solvent liquid of portions of said deposits from the master sheet surface to the duplicate sheet surface in areas thereon representing said image, whereby a duplicate image is formed on said duplicate sheet surface of dark colored material produced by the action of said phenolic substance in said solvent liquid in opening said bond from the methane carbon atom to the heterocyclic oxygen atom to permit quinonoid resonance in the portions of said chromogenous compound trans ferred to the duplicate sheet surface.

14. The method of duplicating, comprising: providing two colorless or lightly colored substances, one of these two substances being a chromogenous compound which includes as its major functional arrangement the molecular structure having a triphenylmethane group with a bond from the methane carbon atom thereof to the heterocyclic oxygen atom, and the other of said two substances being a phenolic substance selected from the group consisting of phenol, resorcinol, pyrocatechol, quinol, phloroglucinol, pyrogallol, hydroxyquinol, l-naphthol, and Z-naphthol; forming on the surface of a master sheet deposits of a preselected one of said two substances in areas representing an image to be duplicated but with mirror-reversed image elements; applying to a surface of a duplicate sheet, which carries on at least said surface the remaining one of said two substances, a liquid which is a solvent for said preselected one of the two substances; and pressing said duplicate sheet surface, wetted with the solvent liquid, against said master sheet surface to cause portions of said preselected one of the two substances deposited thereon to dissolve in said liquid and to be transferred into contact with said remaining one of the two substances, carried on the duplicate sheet surface, in the areas thereon representing said image, whereby a duplicate image is formed on said duplicate sheet surface of dark colored material produced by the action of said phenolic substance in opening said bond from the methane carbon atom to the heterocyclic oxygen atom to permit quinonoid resonance in said chromogenous compound.

15. The method of duplicating, comprising: forming on the surface of a master sheet, in areas representing an image to be duplicated but with mirror-reversed image elements, deposits of a phenolic substance selected from the group consisting of phenol, resorcinol, pyrocatechol, quinol, phloroglucinol, pyrogallol, hydroxyquinal, 1- naphthol, and Z-naphthol; providing a duplicate sheet carrying on at least one active surface a colorless or lightly colored compound which includes as its major functional arrangement the molecular structure having a triphenylmethane group with a bond from the methane, carbon atom thereof to the heterocyclic oxygen atom; applying to said active surface of the duplicate sheet a liquid which is a solvent for said phenolic substance; and pressingrsaid duplicate sheet surface, wetted with the solvent. liquid, against said master sheet surface to cause portions of said deposits of the phenolic substance thereon to dissolve in said liquid and to be transferred into contact with said chromogenous substance, carried on the duplicate sheet surface, in the areas thereon representing said image, whereby a duplicate image is formed on said duplicate sheet surface of dark colored material produced by the action of said transferred portions of the phenolic substance in opening said bond from they methane carbon atom. to the heterocyclic oxygen atom to permit quinonoid resonance in said chromogenous compound carried by said duplicate sheet.

16. A manifolded set, comprising: a first base Web carrying on one side at least onephenolic material selected from the group consisting of phenol, resorcinol, pyrocatechol, quinol, phloroglucinol, pyrogallol, hydroxyquinol, l-naphthol, 2-naphthol; and a second base Web carrying on at least one active surface a lactone chromogenous compound reactive with said phenolic material to develop a quinonoid resonant colored form of said chromogenous compound; said first and second Webs being maintained disposed together in face-to-face relationship with said phenolic material in contiguity with said active surface, whereby upon contact of said phenolic materialand said chromogenous compound, said colored form of said chromogenous compound is produced by the action of said phenolic material on said chromogenous compound.

References Cited by the Examiner UNITED STATES PATENTS 2,449,088 9/1948 Smith 260396 2,554,543 5/1951 Steiger 260396 2,646,367 7/1953 Davis et a1 117-362 2,712,507 7/ 1955 Green 117-362 2,755,201 7/1956 Webber et al 117-36.2 2,870,040 1/1959 Gill 117-362 2,900,388 8/1959 Tien n--. 117-362 2,935,938 5/1960 OSullivan 101-1494 2,939,009 5/ 1960 Tien.

2,972,547 2/1961 Tien 117-362 2,978,352 4/1961. Clarke 117-362 WILLIAM lD. MARTIN, Primary Examiner.

MURRAY KATZ, Examiner. 

1. A MANIFOLDED SET, COMPRISING: A FIRST BASE WEB HAVING ON ONE SIDE A TRANSFER COATING MADE UP OF A FILM-FORMING MATERIAL WHICH IS RUPTURABLE UPON IMPACT AND WHICH CONTAINS AS A FINELY DISPERSED PHASE NUMEROUS CELLS OF A SOLVENT LIQUID VEHICLE; A SECOND BASE WEB HAVING ON ONE SIDE AN ADHERENT COATING, SAID FIRST AND SECOND WEBS BEING MAINTAINED DISPOSED TOGETHER IN FACE TO FACE RELATIONSHIP WITH SAID RESPECTIVE TRANSFER AND ADHERENT COATINGS IN CONTIGUITY WITH EACH OTHER; ONE COATING CONSTITUENT IN THE FORM OF A COLORLESS OR LIGHTLY COLORED CHROMOGENOUS COMPOUND WHICH INCLUDES AS ITS MAJOR FUNCTIONAL ARRANGEMENT THE MOLECULAR STRUCTURE 